fix: Fix remaining 61 ruff linting errors (SIM102, SIM117)

Fixed all remaining linting errors from the 310 total:
- SIM102: Combined nested if statements (31 errors)
  - adaptors/openai.py
  - config_extractor.py
  - codebase_scraper.py
  - doc_scraper.py
  - github_fetcher.py
  - pattern_recognizer.py
  - pdf_scraper.py
  - test_example_extractor.py

- SIM117: Combined multiple with statements (24 errors)
  - tests/test_async_scraping.py (2 errors)
  - tests/test_github_scraper.py (2 errors)
  - tests/test_guide_enhancer.py (20 errors)

- Fixed test fixture parameter (mock_config in test_c3_integration.py)

All 700+ tests passing.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/skill_seekers/cli/test_unified_simple.py

@@ -143,7 +143,7 @@ def test_config_validation_errors():
         try:
             # validate_config() calls .validate() automatically
             _validator = validate_config(config_path)
-            assert False, "Should have raised error for invalid source type"
+            raise AssertionError("Should have raised error for invalid source type")
         except ValueError as e:
             assert "Invalid" in str(e) or "invalid" in str(e)
             print("  ✓ Invalid source type correctly rejected")